Heat exchangers are used in many systems, from cars to air-conditioning units to energy recovery devices in advanced thermal treatment systems.
Conventionally, the design of heat exchangers has to take into account various factors. For example, fouling may cause increased pressure drop and reduced heat transfer rate which can have a detrimental effect on heat exchanger efficiency. As another consideration, heat exchangers by their nature will experience temperature variation. In addition, heat exchangers may be subject to high velocity fluid (gas or liquid) flows with particulate loading that elevates wear rates for certain areas of the system. Erosion problems can be exacerbated when a heat exchanger operates at an elevated temperature. Similarly, fluids passing through a heat exchanger may contain acids or other corrosive materials, which may even degrade the interior of a heat exchanger more at elevated temperatures. Corrosion and erosion problems may be particularly prevalent in metallic heat exchangers
In some conventional ceramic heat exchangers, a tube-to-tubesheet construction is employed. A first fluid flows inside a series of tubes while a second fluid flows over the outside of the tubes. On contact with the tubes, therefore, the second fluid can stagnate, which can lead to a number of problems. For example, if the second fluid contains particulates, the surface of the tubes normal to the flow of the second fluid will experience increased erosion. Also, in some situations, the stagnation points around the tubes will lead to fouling.
There is a need for methods and apparatus that allow efficient heat exchange between fluids.